Method for transmitting a signal

ABSTRACT

The method includes providing a stream of data to be transmitted, and processing the data by means of channel coding with a time-varying code rate, thereby generating a stream of channel coded data. The method further includes forming succeeding transmission time intervals and distributing the channel coded data on the transmission time intervals, and adjusting a transmission power of the signal to be transmitted by timely positioning a transmission power slope between two succeeding transmission time intervals so that the transmission power slope is contained completely within one transmission time interval of the two transmission time intervals, wherein the one transmission time interval comprises a lower nominal code rate or a lower nominal transmission power than the other one of the two transmission time intervals.

REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.13/083,675 filed on Apr. 11, 2011.

FIELD

The present invention relates to a method for transmitting a signal in amobile communication system and a transmitter for transmitting a signalin a mobile communication system.

BACKGROUND

In a mobile communication system the data rate can be adapteddynamically for efficiency reasons. The power of the transmitted signalalso changes due to the data rate as every successfully transmitted bitmust be paid for with a certain amount of transmitted energy. In atransmitter of a mobile communication system channel coding is usuallyemployed, providing bit redundancy for the purpose of error protection.Channel coding can be employed with timely varying code rates. As veryhigh code rates result in very low redundancy a problem arises inparticular for certain modulation schemes when any amplitude variationis present in the transmitted signal.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of embodiments and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments andtogether with the description serve to explain principles ofembodiments. Other embodiments and many of the intended advantages ofembodiments will be readily appreciated as they become better understoodby reference to the following detailed description.

FIG. 1 shows a flow diagram of a method for transmitting a signal in amobile communication system according to an embodiment;

FIG. 2 shows a time diagram of a nominal transmission power according toa transport format change (a) and a variation of the transmission power(b);

FIG. 3 shows a schematic block representation of a transmitter fortransmitting a signal in a mobile communication system according to anembodiment; and

FIG. 4 shows a schematic block representation of a transmitter fortransmitting a signal in a mobile communication system.

DETAILED DESCRIPTION

The aspects and embodiments are described with reference to thedrawings, wherein like reference numerals are generally utilized torefer to like elements throughout. In the following description, forpurposes of explanation, numerous specific details are set forth inorder to provide a thorough understanding of one or more aspects of theembodiments. It may be evident, however, to one skilled in the art thatone or more aspects of the embodiments may be practiced with a lesserdegree of the specific details. In other instances, known structures andelements are shown in schematic form in order to facilitate describingone or more aspects of the embodiments. It is to be understood thatother embodiments may be utilized and structural or logical changes maybe made without departing from the scope of the present invention.

In addition, while a particular feature or aspect of an embodiment maybe disclosed with respect to only one of several implementations, suchfeature or aspect may be combined with one or more other features oraspects of the other implementations as may be desired and advantageousfor any given or particular application. Furthermore, to the extent thatthe terms “include”, “have”, “with” or other variants thereof are usedin either the detailed description or the claims, such terms areintended to be inclusive in a manner similar to the term “comprise”. Theterms “coupled” and “connected”, along with derivatives may be used. Itshould be understood that these terms may be used to indicate that twoelements co-operate or interact with each other regardless whether theyare in direct physical or electrical contact, or they are not in directcontact with each other. Also, the term “exemplary” is merely meant asan example, rather than the best or optimal. The following detaileddescription, therefore, is not to be taken in a limiting sense, and thescope of the present invention is defined by the appended claims.

The methods and apparatuses as described herein are utilized as part ofand for mobile communication systems, in particular systems operatingaccording to one of the 3G mobile communication standards. Moreparticularly, the mobile communication systems may employ one or more ofthe Universal Mobile Telecommunications Systems (UMTS) Standard or theHigh Speed Packet Access (HSPA) Standard or the Long Term Evolution(LTE) Standard.

The method and apparatuses as described herein may be embodied intransmitters like base-stations or relay-stations as well as in mobilephones, hand-held devices or other kinds of mobile radio transmitters.The described apparatuses may be employed to perform methods asdisclosed herein, although those methods may be performed in any otherway as well.

The methods and apparatuses as described herein may also be utilizedwith any sort of antenna configurations employed within the mobilecommunication system. In particular, the concepts presented herein areapplicable to mobile communication systems employing more than onetransmit and/or receive antenna and in particular an arbitrary number oftransmit and/or receive antennas.

Referring to FIG. 1, there is shown a flow diagram of a method fortransmitting a signal in a mobile communication system according to anembodiment. The method comprises providing a stream of data to betransmitted at s1, and processing the data by means of channel codingwith a time-varying code rate, thereby generating a stream of channelcoded data at s2. The method further comprises forming succeedingtransmission time intervals and distributing the channel coded data onthe transmission time intervals at s3, and adjusting a transmissionpower of the signal to be transmitted by timely positioning atransmission power slope between two succeeding transmission timeintervals so that the transmission power slope is contained completelywithin one transmission time interval of the two transmission timeintervals, wherein the one transmission time interval comprises a lowernominal code rate or a lower nominal transmission power than the otherone of the two transmission time intervals at s4.

According to an embodiment of the method of FIG. 1, adjusting thetransmission power is performed as follows. The transmission power slopecan either be a transmission power increase or a transmission powerdecrease between two succeeding transmission time intervals. If thenominal code rate or the nominal transmission power is to be increasedfrom a relatively low value in a first transmission time interval to arelatively high value in a second transmission time interval, then atransmission power increase will completely occur within the precedingfirst transmission time interval, and if the nominal code rate or thenominal transmission power is to be decreased from a relatively highvalue in a first transmission time interval to a relatively low value ina second transmission time interval, then a transmission power decreasewill completely occur within the succeeding second transmission timeinterval.

The term “nominal” as used in the foregoing within the terms “nominalcode rate” or “nominal transmission power” is intended to be similar tothe terms “intended”, “pre-defined”, “pre-determined”, or“pre-calculated”. For any given transmission time interval a so-calledtransport format is chosen beforehand which defines certain parametersor values of parameters of the transmission time interval as, forexample, the channel coding, the modulation, or the transmission power.These parameters or values or at least some of them or all of them canbe defined to be constant throughout the transmission time interval orat least constant throughout particular slots of the transmission timeinterval. The transport format can be chosen or selected by the basebandsection of the transmitter of the communication unit.

It is one essential advantage of the method of FIG. 1 that it guaranteesan essentially steady and constant transmission power level throughoutthe transmission time interval which carries data of a relatively highnominal code rate and corresponding low bit error redundancy. Thistransmission time interval is essentially free of too high power levelvariations. As a consequence, even for particular modulation schemes, itwill be an easy task for a channel decoder at a receiver's site todecode the incoming channel coded data.

According to an embodiment of the method of FIG. 1, the method is alsoapplied in situations in which one of the two adjacent transmission timeintervals is virtually empty, i.e. being a transmission time interval inwhich no transmission occurs or no data are transmitted. In other wordsone can say that such a transmission time interval can be treated as atransmission time interval having low, namely zero, nominal code rate orlow, namely zero, nominal transmission power.

It is to be noted that the method of FIG. 1 contains an alternative fordeciding about the timely positioning, namely either the onetransmission time interval comprises a lower nominal code rate or alower nominal transmission power. It should be stated that in apractical implementation it might be easier to implement the secondalternative, namely to look at the nominal transmission power. In mostcases the result will be the same as would have been when taking thefirst alternative. However, one advantage can be that the implementationcan be easier as the nominal transmission power is in any case known inthe radiofrequency section of the transmission, whereas the nominal coderate is not necessarily known in the radiofrequency section and must betransmitted to the radiofrequency section in case of the firstalternative.

According to an embodiment of the method of FIG. 1, the time duration ofa transmission power slope is made below 50 μs, more particularly below40 μs, and more particularly below 30 μs. In an embodiment presentedbelow the duration will be about 25 μs. This value can be defined suchthat it relates to a power step between certain values of percentage ofthe nominal upper power level like, for example, 10% (5%) of the upperpower level as a low value and 90% (95%) of the upper power level as ahigh value.

A mobile communication system functioning according to one of the 3Gstandards has to deal with dynamic data rates requested by theapplication layer using packet-switched (PS) connection. The lowerlayers down to the physical layer also adapt their data ratesdynamically for efficiency reasons (e.g. cell capacity, powerconsumption etc.). The adaptation of the data rate can be done by thephysical layer once per transmission time interval while thesetransmission time intervals are transmitting seamless in time.

In general the physical layer consists of a baseband and a radiofrequency component. For a given transmission time interval the basebandchooses a transport format according to the instantaneous data rate. Thetransport format defines the channel coding or modulation and thetransmit power. By this the quality of service like block error rate canbe made approximately independent from the instantaneous data rate. Thegenerated baseband signal is afterwards transmitted by the radiofrequency component with the previous calculated transmit power.Therefore, the radio frequency component has to change the transmitpower for every transmission time interval.

The radio frequency component can, however, not change the transmitpower instantaneously. Since high data rates like those used in highspeed packet access (HSPA) result in power changes of more than 20 dBm,the real change of the transmit power can easily make the reception ofthe effected transmission time intervals impossible. This results inlower throughput and worse user experience in dynamic data ratepacket-switched connections.

In a mobile communication system working according to one of the 3Gstandards, requirements of the radio frequency component are definedabout e.g. the error vector magnitude (EVM) in order to guarantee thequality of the transmitted signal. Any unintentional change in transmitpower could cause these requirements to fail. Since the radio frequencycomponent can not instantaneously change the transmission power,transient periods are given in which the transmission power is changedfrom one value to the other. During these transient periods norequirements like EVM are made and the radio frequency component isallowed to change the transmission in principle with an arbitrary slope.By this it is guaranteed that the transmission time interval isessentially unaffected by the power change.

Referring to FIGS. 2 a and 2 b, there is shown time diagrams: one of anominal transmission power of transport format change (FIG. 2 a), andthe other a time-dependent real or effective transmission power (FIG. 2b) according to an embodiment. FIG. 2 a represents a typical HSUPAtransport format (E-TFC) change scenario. In this embodiment thetransmission time interval (TTI) has a length of 2 ms and is divided in3 slots with a length of 2560 bits each. For each TTI a special E-TFCselection procedure is performed, setting particular parameters for thetransport block size, the error protection scheme, the coding rate, themodulation etc. These parameters are listed in tables together withinteger E-TFCI values, each one of them designating a particular set ofparameters. In addition, the amount of transmission power required totransmit a given E-TFC is calculated. This calculated transmit power isshown in FIG. 2 a. The power of the up-link control channel DPCCH isonly driven by the inner loop power control (ILPC) while the power ofthe data carrying up-link EDCH channel also changes due to the transportformat change. The number of data bits per transmission time interval isgiven as transport block size. In the figure the first transmission timeinterval (E-TFCI=0) on the left (only two slots are shown) has atransport block size of 18 data bits changing to a transport block sizeof 22996 data bits in the second transmission time interval(E-TFCI=124), and thereafter changing back to a transport block size of18 data bits in the third transmission time interval (only one slot isshown). The transmit power mainly scales with the transport block sizesince the data bits must be paid for with a certain amount oftransmitted energy. This results in a calculated transmit power changeof ±20 dBm or even more than that.

The mobile communication system as used in the scheme of FIGS. 2 a and 2b is able to apply channel coding with very high code rates offeringvery low redundancy. In one embodiment the 3G high speed up-link packetaccess (HSUPA) uses 4PAM modulation with code rates up to R=0.9991.Thus, the available redundancy covers only 0.09% of the modulated bits.The reception of a 4PAM modulated signal becomes unreliable or evenimpossible when any amplitude error is present in the correspondingtransmission time interval like that shown in FIGS. 2 a and 2 b.

Therefore, the position of the transmission power slope is adapted tothe baseband signal coding or modulation used in the effectedtransmission time intervals. FIG. 2 b shows the real or effectivetransmission power. As shown in FIG. 2 b, one aspect of this embodimentis that the position of the transmission power slopes is timelypositioned in transmission time intervals having stronger codingcorresponding to lower nominal code rates. The code rate of the twoadjacent transmission time intervals is R=0.175 whereas the code rate ofthe intermediate transmission time interval is R=0.9991.

For HSUPA smaller transport blocks always have stronger coding ormodulation. Hence, one can assume that for every transport formatchange, causing high transmit power change, a transmission time intervalwith strong coding or modulation is present. Otherwise there would be nochange in transport block size and subsequent transmit power. In FIG. 2b the transmission power slope is positioned in the left TTI for thefirst transport format change and positioned in the right TTI for thesecond transport format change. In addition it is shown in FIG. 2 b thatthe duration of the transmission power slopes is about 25 μs. Inparticular it can be defined that this value relates to a power stepbetween 10% (5%) and 90% (95%) of the upper power level. As a result,all transmission time intervals in FIG. 2 b above can be received anddecoded successfully and no throughput degradation is observed. Inaddition the presented solution fulfills the 3GPP requirements since thetransmission power is still adjusted within the transient period.

According to an embodiment of the method of FIG. 1, the timelypositioning of the transmission power slope according to step s4 canalso be coupled to a condition. For example, it can be determined thatone of the two succeeding transmission time intervals comprises arelatively low nominal code rate and the other one of the two succeedingtransmission time intervals comprises a relatively high nominal coderate and that the timely positioning of the transmission power slope isperformed only in a situation in which the difference between therelatively low nominal code rate and the relatively high nominal coderate is above a certain predetermined threshold. Another possiblecondition for performing the step s4 can be that the relatively highvalue of the nominal code rate is above a certain predeterminedthreshold value. It is also possible that both above-defined conditionscan be added together. If the condition or the conditions are notfulfilled, then the transmission power change can be done according toany other method within the frame of the requirements of thecorresponding 3G standard.

According to an embodiment of the method of FIG. 1, the method iscarried out in a transmitter comprising a baseband section and a radiofrequency section, and the method further comprises determining thetimely position of the transmission power slope in the baseband section.According to an embodiment thereof, determining the timely position ofthe transmission power slope is performed according to the timelyvarying nominal code rate or the timely varying nominal transmissionpower. Furthermore, it is also possible that the baseband sectiongenerates a baseband signal and the transmission power slope is includedor incorporated within the baseband signal.

According to an embodiment of the method of FIG. 1, the method iscarried out in a transmitter comprising a baseband section and a radiofrequency section and the method further comprises determining thetimely position of the transmission power slope in the radio frequencysection. Within this embodiment it is also possible that the timelyposition of the transmission power slope is determined according to thetimely varying nominal code rate or the timely varying nominaltransmission power.

According to an embodiment of the method of FIG. 1, the mobilecommunication system functions according to a 3G High Speed PacketAccess (HSPA) standard.

According to an embodiment of the method of FIG. 1, the mobilecommunication system functions according to a 3G Long Term Evolution(LTE) standard.

Referring to FIG. 3, there is shown a schematic block representation ofa transmitter for transmitting a signal in a mobile communicationsystem. The transmitter 10 shows a channel coding unit 1 configured toreceive a stream of data and perform a channel coding operation with atime-varying code rate. The transmitter 10 also comprises a transmissionpower adjusting unit 2 configured to adjust a transmission power of thesignal to be transmitted by timely positioning a transmission powerslope between two succeeding transmission time intervals so that thetransmission power slope is contained completely within one transmissiontime interval of the two transmission time intervals, wherein the onetransmission time interval comprises a lower nominal code rate or alower nominal transmission power than the other one of the twotransmission time intervals.

According to an embodiment of the transmitter of FIG. 3, thetransmission power adjusting unit 2 is configured to adjust the timeduration of the transmission power slope to below 50 μs, moreparticularly 40 μs, and more particularly 30 μs. Regarding thedefinition of the time duration, reference is made to the above.

According to an embodiment of the transmitter of FIG. 3, thetransmission power adjusting unit 2 is configured to perform the step oftimely positioning the transmission power slope only under a predefinedcondition. In particular, it can be assumed that one of the twosucceeding transmission time intervals comprises a relatively lownominal code rate and the other one of the two succeeding transmissiontime intervals comprises a relatively high nominal code rate. Thecondition can be such that the difference between the relatively lownominal code rate and the relatively high nominal code rate is above acertain predetermined threshold. The transmission power adjusting unitis configured to timely position the transmission power slope accordingto other requirements like the general requirements as set in the 3Gstandard if the condition is not fulfilled. Alternatively, or inaddition thereto, the transmission power adjusting unit is configured toperform the timely positioning only under the condition that therelatively high value of the nominal code rate is above a certainpredetermined threshold value, otherwise following other requirementslike 3G standard requirements.

According to an embodiment of the transmitter of FIG. 3, the transmitter10 comprises a baseband section and a radio frequency section, and thechannel coding unit 1 and the transmission power adjusting unit 2 arearranged in the baseband section. According to an embodiment thereof,the transmission power adjusting unit 2 is configured to determine thetimely position of the transmission power slope according to the timelyvarying nominal code rate or to the timely varying nominal transmissionpower. Moreover, it can be provided that the baseband section isconfigured to generate a baseband signal, and the transmission poweradjusting unit 2 is configured to incorporate the transmission powerslope into the baseband signal.

According to an embodiment of the transmitter of FIG. 3, the transmitter10 comprises a baseband section and a radio frequency section, and thechannel coding unit is arranged in the baseband section and thetransmission power adjusting unit 2 is arranged in the radio frequencysection.

According to an embodiment thereof, the transmission power adjustingunit 2 is configured to determine the timely position of thetransmission power slope according to the timely varying nominal coderate or to the timely varying nominal transmission power.

According to one embodiment of the transmitter of FIG. 3, the channelcoding unit 1 is a convolutional coder or a turbo coder.

Referring to FIG. 4, there is shown a schematic block representation ofa transmitter for transmitting a signal in a mobile communication systemaccording to an embodiment. The transmitter 20 comprises a basebandsection 21 comprising a channel coding section 21.1 configured tochannel code a stream of date with a time-varying code rate. Thetransmitter 20 further comprises a transmission power adjusting unit(TPAU) 22 configured to adjust a transmission power of the signal to betransmitted by timely positioning a transmission power slope between twosucceeding transmission time intervals so that the transmission powerslope is contained completely within one transmission time interval ofthe two transmission time intervals, wherein the one transmission timeinterval comprises a lower nominal code rate or a lower nominaltransmission power than the other one of the two transmission timeintervals. The transmitter 20 further comprises a radio frequencysection 23 coupled to the baseband section 21 to receive therefrom astream of channel coded date.

According to an embodiment of the transmitter of FIG. 3, thetransmission power adjusting unit 22 is part of the baseband section 21.According to an embodiment thereof, the transmission power adjustingunit 22 is configured to incorporate the transmission power slope intothe baseband signal. Furthermore, the transmission power adjusting unit22 can be configured to determine the timely position of thetransmission power slope according to a timely varying nominal code rateor to a timely varying nominal transmission power.

According to an embodiment of the transmitter of FIG. 3, thetransmission power adjusting unit 22 is part of the radio frequencysection 23. According to an embodiment thereof, the transmission poweradjusting unit 22 is configured to determine the timely position of thetransmission power slope according to the timely varying nominal coderate or to the timely varying nominal transmission power.

1. A method for transmitting a signal in a mobile communication system,comprising: providing a plurality of data packets to be transmitted;processing the data by channel coding with a variable code rate, therebygenerating a plurality of channel coded data; forming succeedingtransmission time intervals and distributing the channel coded data onthe transmission time intervals; and adjusting a transmission power ofthe signal to be transmitted by positioning at least one transmissionpower slope at a specific point of time between two succeedingtransmission time intervals so that the at least one transmission powerslope is contained completely within one transmission time interval ofthe two transmission time intervals, wherein the one transmission timeinterval comprises a lower nominal code rate or a lower nominaltransmission power than the other one of the two transmission timeintervals, wherein one of the two succeeding transmission time intervalscomprises a first nominal code rate or a first nominal transmissionpower and the other one of the two succeeding transmission timeintervals comprises a second nominal code rate or a second nominaltransmission power, respectively, and wherein the second nominal coderate or the second nominal transmission power is greater than the firstnominal code rate or the first nominal transmission power, respectively,the method further comprising: adjusting the transmission power if thesecond nominal code rate or the second nominal transmission power isabove a predetermined threshold value.
 2. The method according to claim1, wherein the time duration of a transmission power slope is below 50μs.
 3. The method according to claim 1, wherein the method is carriedout in a transmitter comprising a baseband section and a radio frequencysection, the method further comprising: determining the timely positionof the transmission power slope in the baseband section.
 4. The methodaccording to claim 3, further comprising: determining the timelyposition of the transmission power slope according to a variable nominalcode rate or a variable nominal transmission power.
 5. The methodaccording to claim 3, wherein the baseband section generates a basebandsignal and the transmission power slope is included in the basebandsignal.
 6. The method according to claim 1, wherein the method iscarried out in a transmitter comprising a baseband section and a radiofrequency section, the method further comprising: determining the timelyposition of the transmission power slope in the radio frequency section.7. The method according to claim 6, further comprising: determining thetimely position of the transmission power slope according to a variablenominal code rate or a variable nominal transmission power.
 8. Themethod according to claim 1, wherein the mobile communication systemoperates according to a 3G High Speed Packet Access (HSPA) standard. 9.The method according to claim 1, wherein the mobile communicationsystems operates according to a 3G Long Term Evolution (LTE) standard.10. A transmitter for transmitting a signal in a mobile communicationsystem, comprising: a channel coding unit configured to receive aplurality of data packets to be transmitted and perform a channel codingoperation with a variable code rate; and a transmission power adjustingunit configured to adjust a transmission power of the signal to betransmitted by positioning a transmission power slope at a specificpoint of time between two succeeding transmission time intervals so thatthe transmission power slope is contained completely within onetransmission time interval of the two transmission time intervals,wherein the one transmission time interval comprises a lower nominalcode rate or a lower nominal transmission power than the other one ofthe two transmission time intervals, wherein one of the two succeedingtransmission time intervals comprises a first nominal code rate and theother one of the two succeeding transmission time intervals comprises asecond nominal code rate, and wherein the second nominal code rate isgreater than the first nominal code rate, and wherein the transmissionpower adjusting unit is configured to position the transmission powerslope at a specific point of time between two succeeding transmissiontime intervals only if the second nominal code rate is above apredetermined threshold value.
 11. The transmitter according to claim10, wherein the transmission power adjusting unit is configured toadjust the time duration of the transmission power slope to below 50 μs.12. The transmitter according to claim 10, further comprising: abaseband section and a radio frequency section, wherein the channelcoding unit and the transmission power adjusting unit are arranged inthe baseband section.
 13. The transmitter according to claim 12, whereinthe transmission power adjusting unit is configured to determine theposition of the transmission power slope according to the variablenominal code rate or to the variable nominal transmission power.
 14. Thetransmitter according to claim 12, wherein the baseband section isconfigured to generate a baseband signal, and the transmission poweradjusting unit is configured to incorporate the transmission power slopeinto the baseband signal.
 15. The transmitter according to claim 10,further comprising: a baseband section and a radio frequency section,wherein the channel coding unit is arranged in the baseband section andthe transmission power adjusting unit arranged in the radio frequencysection.
 16. The transmitter according to claim 15, wherein thetransmission power adjusting unit is configured to determine theposition of the transmission power slope according to a variable nominalcode rate or a variable nominal transmission power.
 17. A transmitterfor transmitting a signal in a mobile communication system, comprising:a channel coding unit configured to receive a plurality of data packetsto be transmitted and perform a channel coding operation with a variablecode rate; and a transmission power adjusting unit configured to adjusta transmission power of the signal to be transmitted by positioning atransmission power slope at a specific point of time between twosucceeding transmission time intervals so that the transmission powerslope is contained completely within one transmission time interval ofthe two transmission time intervals, wherein the one transmission timeinterval comprises a lower nominal code rate or a lower nominaltransmission power than the other one of the two transmission timeintervals, and the transmission power adjusting unit further configuredto adjust the transmission power according to the following: if anominal code rate or a nominal transmission power is to be increasedfrom a first value in a first transmission time interval to a secondvalue in a second transmission time interval, wherein the second valueis greater than the first value, then a transmission power increase willcompletely occur within the first transmission time interval, and if thenominal code rate or the nominal transmission power is to be decreasedfrom a third value in a first transmission time interval to a fourthvalue in a second transmission time interval, wherein the fourth valueis less than the third value, then a transmission power decrease willcompletely occur within the second transmission time interval.
 18. Thetransmitter according to claim 17, wherein the transmission poweradjusting unit is configured to adjust the time duration of thetransmission power slope to below 50 μs.
 19. The transmitter accordingto claim 17, further comprising: a baseband section and a radiofrequency section, wherein the channel coding unit and the transmissionpower adjusting unit are arranged in the baseband section.
 20. Thetransmitter according to claim 19, wherein the transmission poweradjusting unit is configured to determine the position of thetransmission power slope according to the variable nominal code rate orto the variable nominal transmission power.
 21. The transmitteraccording to claim 19, wherein the baseband section is configured togenerate a baseband signal, and the transmission power adjusting unit isconfigured to incorporate the transmission power slope into the basebandsignal.
 22. The transmitter according to claim 17, further comprising: abaseband section and a radio frequency section, wherein the channelcoding unit is arranged in the baseband section and the transmissionpower adjusting unit arranged in the radio frequency section.
 23. Thetransmitter according to claim 22, wherein the transmission poweradjusting unit is configured to determine the position of thetransmission power slope according to a variable nominal code rate or avariable nominal transmission power.
 24. A method for transmitting asignal in a mobile communication system, comprising: providing aplurality of data packets to be transmitted; processing the data by aplurality of different modulation schemes to generate modulated data;forming a plurality of succeeding transmission time intervals anddistributing the modulated data on the plurality of transmission timeintervals; and adjusting a transmission power of the signal to betransmitted by positioning at least one transmission power slope at aspecific point of time between the plurality of succeeding transmissiontime intervals to contain the at least one transmission power slopecompletely within one of the plurality of transmission time intervals,wherein the plurality of succeeding transmission time intervals comprisethe plurality of different modulation schemes.
 25. The method accordingto claim 24, wherein positioning the transmission power slope is carriedout based on amplitude variations in the different modulation schemes.